As sensors for validating individuals there are facial validation sensors for validating a user through the use of an image of a face or the use of a feature quantity extracted from an image of a face (hereinafter termed, in general, “facial image data”).
This type of facial validation sensor validates a user by matching facial image data, obtained through the use of a camera to image the face of the individual to be validated (input facial image data), with facial image data that has been registered in advance (registered facial image data).
Consequently, in order to perform accurate validation using facial image data, preferably, when obtaining the input facial image data, the orientation of the face in the input facial image data in the imaging region of the facial validation sensor is always the same orientation (for example, “face forward”) as in the registered facial image data. Given this, the facial validation sensor must have a feedback unit that guides the face of the person to be validated into the imaging region that is imaged by the camera.
In conventional facial validation sensors there has been a proposal, such as in Japanese Unexamined Patent Application Publication 2007-4613 (“the JP '613”), for the placement of a convex mirror in the vicinity of a wide-angle camera to enable each individual to be validated to visually check his or her own face in a portion of the mirror, so that the face will reliably be facing the convex mirror and the wide-angle camera when the face is imaged, in order to capture facial images that are facing the same direction even when there is variability in the stature of the individuals to be validated, as the feedback unit that guides the face of the individual to be validated into the imaging region that is imaged by the camera.
However, even though the technology disclosed in the JP '613 is able to cause the individual to be validated to direct his or her face in a specific direction, the region that is reflected in the convex mirror changes depending on the distance from the convex mirror, thus making it difficult to ensure a distance from the camera wherein the face of the individual to be validated will be within the imaging region of the facial validation sensor, and thus there was the danger that the face of interest would extend outside of the imaging region of the facial validation sensor, producing variability in the validation results.
Given this, the object of the present invention is to provide a facial validation sensor that is both able to cause the face of the individual to be validated to face in a specific direction, and able to induce the face of the individual to be validated into the imaging region of the facial validation sensor regardless of the distance between the individual to be validated and the camera.